Ow Ow Ow, Ow Ow Whaow, Ow Ow Ow...Wha-aa-ow. That simple G-minor melody, supposedly inspired by Beethoven's Fifth Symphony (or perhaps Brazilian composer Carlos Lyra) and played with the tone of a Fender Stratocaster doubled by a Hammond B3 organ, is unquestionably the most famous rock-guitar riff. The apotheosis of 1970s hard-rock, the ubiquitous "Smoke on the Water" is also the unlikely story of the song's creation and the high-water mark of long-running UK rock band Deep Purple.